Communication System — Physics STD 12 Science — Question

What is the momentum of a photon having frequency 1.5 

(a) 3.3	(b) 3.3
(c) 6.6	(d) 6.6

When the N-pole of a bar magnet points towards the south and S-pole towards the north, the null points are at the

(a) Magnetic axis	(b) Magnetic centre
(c) Perpendicular divider of magnetic axis	(d) N and S poles

Current in the circuit is wattless, if.

The magnetic potential at a point on the axial line of a bar magnet of dipole moment M is V. What is the magnetic potential due to a bar magnet of dipole moment  at the same point

(a) 4V

(b) 2V

(c)

(d)

The binding energy per nucleon is maximum in the case of

(a)

(b)

(c)

(d)

A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is   and the fish is 12 cm below the surface, the radius of this circle in cm is

(a) 36

(b) 4

(c) 36

(d) 36/

The angular momentum of electrons in an atom produces:

A moving coil galvanometer has N number of turns in a coil of effective area A, it carries a current I. The magnetic field B is radial. The torque acting on the coil is

(a)

(b)

(c)

(d) NABI